Techniques for managing wireless transmission energy budget

ABSTRACT

Techniques are disclosed relating to wireless transmission energy budgets. In some embodiments, an apparatus is configured to determine wireless transmission energy budget for a plurality of time periods. In some embodiments, the apparatus determines budget differently depending on whether it is in a thermal mode or a peak power mode. In some embodiments, the apparatus blanks scheduled wireless transmissions that intersect with the battery signal. In some embodiments, for a time interval subsequent to assertion of the battery signal, the apparatus operates in the peak power mode and determines energy budget for periods based on an amount of energy used for wireless transmissions in a most recent period in which transmissions were blanked in response to the battery signal. In some embodiments, in the thermal mode, the energy budget is based on thermal information for the apparatus, but may also allow carryover of unused budget from previous periods.

TECHNICAL FIELD

The present application relates to wireless communication, and inparticular to determining an energy budget for wireless transmissions.

DESCRIPTION OF THE RELATED ART

Wireless communication systems are rapidly growing in usage. Further,wireless communication technology has evolved from voice-onlycommunications to also include the transmission of data, such asInternet and multimedia content.

Mobile electronic devices may take the form of smart phones or tabletsthat a user typically carries. Wearable devices (also referred to asaccessory devices) are a newer form of mobile electronic device, oneexample being smart watches. Typically, wearable devices have hadlimited wireless communications capabilities and were capable ofcommunicating only over wired interfaces or short-range point-to-pointtechnologies. Wearable devices typically have smaller batteries thanlarger portable devices, such as smart phones and tablets. Wearabledevices also may have different thermal characteristics that largerdevices, e.g., because of their small size. Wireless transmissions usingwearable devices may cause current spikes and/or thermal spikes whichcan damage equipment and substantially reduce battery life.

SUMMARY

Embodiments are presented herein of, inter alia, wireless circuitry fora mobile device such as an accessory device, and associated methods fordetermining and satisfying a wireless transmission energy budget.

In some embodiments, an apparatus is configured to determine wirelesstransmission energy budget for a plurality of time periods, which may beconsecutive and non-overlapping. The length of the time periods is 40 msin some embodiments, but may be programmable or may vary in differentembodiments. In some embodiments, the apparatus determines budgetdifferently depending on whether it is in a thermal mode or a peak powermode. The apparatus may enter the peak power mode in response to abattery signal, e.g., indicating that battery voltage has dropped. Insome embodiments, the apparatus blanks scheduled wireless transmissionsthat intersect with the battery signal. In some embodiments, for a timeinterval subsequent to assertion of the battery signal, the apparatusoperates in the peak power mode and determines energy budget for periodsbased on an amount of energy used for wireless transmissions in a mostrecent period in which transmissions were blanked in response to thebattery signal. In some embodiments, in the thermal mode, the energybudget is based on thermal information for the apparatus, but may alsoallow carryover of unused budget from previous periods. In someembodiments the disclosed techniques may allow for efficient wirelesstransmission by link-budget-limited devices while satisfying thermaland/or power constraints.

This Summary is intended to provide a brief overview of some of thesubject matter described in this document. Accordingly, it will beappreciated that the above-described features are merely examples andshould not be construed to narrow the scope or spirit of the subjectmatter described herein in any way. Other features, aspects, andadvantages of the subject matter described herein will become apparentfrom the following Detailed Description, Figures, and Claims.

BRIEF DESCRIPTION OF THE DRAWINGS

A better understanding of the present subject matter can be obtainedwhen the following detailed description of the embodiments is consideredin conjunction with the following drawings.

FIG. 1 illustrates an example wireless communication system including anaccessory device;

FIG. 2 illustrates an example system where an accessory device canselectively either directly communicate with a cellular base station orutilize the cellular capabilities of an intermediate or proxy devicesuch as a smart phone;

FIG. 3 is a block diagram illustrating an example accessory device;

FIG. 4 is a block diagram illustrating wireless communication circuitry,according to some embodiments.

FIG. 5 is a flow diagram illustrating a method for determining wirelesstransmission budget for a cycle, according to some embodiments.

FIGS. 6A-6B illustrate exemplary scheduled transmissions and energybudgets for multiple cycles, according to some embodiments.

FIG. 7 is a flow diagram illustrating a method, according to someembodiments.

While the features described herein are susceptible to variousmodifications and alternative forms, specific embodiments thereof areshown by way of example in the drawings and are herein described indetail. It should be understood, however, that the drawings and detaileddescription thereto are not intended to be limiting to the particularform disclosed, but on the contrary, the intention is to cover allmodifications, equivalents and alternatives falling within the spiritand scope of the subject matter as defined by the appended claims.

The term “configured to” is used herein to connote structure byindicating that the units/circuits/components include structure (e.g.,circuitry) that performs the task or tasks during operation. As such,the unit/circuit/component can be said to be configured to perform thetask even when the specified unit/circuit/component is not currentlyoperational (e.g., is not on). The units/circuits/components used withthe “configured to” language include hardware—for example, circuits,memory storing program instructions executable to implement theoperation, etc. Reciting that a unit/circuit/component is “configuredto” perform one or more tasks is expressly intended not to invokeinterpretation under 35 U.S.C. § 112(f) for that unit/circuit/component.

DETAILED DESCRIPTION Terminology

The following is a glossary of terms used in this disclosure:

Memory Medium—Any of various types of non-transitory memory devices orstorage devices. The term “memory medium” is intended to include aninstallation medium, e.g., a CD-ROM, floppy disks, or tape device; acomputer system memory or random access memory such as DRAM, DDR RAM,SRAM, EDO RAM, Rambus RAM, etc.; a non-volatile memory such as a Flash,magnetic media, e.g., a hard drive, or optical storage; registers, orother similar types of memory elements, etc. The memory medium mayinclude other types of non-transitory memory as well or combinationsthereof. In addition, the memory medium may be located in a firstcomputer system in which the programs are executed, or may be located ina second different computer system which connects to the first computersystem over a network, such as the Internet. In the latter instance, thesecond computer system may provide program instructions to the firstcomputer for execution. The term “memory medium” may include two or morememory mediums which may reside in different locations, e.g., indifferent computer systems that are connected over a network. The memorymedium may store program instructions (e.g., embodied as computerprograms) that may be executed by one or more processors.

Carrier Medium—a memory medium as described above, as well as a physicaltransmission medium, such as a bus, network, and/or other physicaltransmission medium that conveys signals such as electrical,electromagnetic, or digital signals.

Programmable Hardware Element—includes various hardware devicescomprising multiple programmable function blocks connected via aprogrammable interconnect. Examples include FPGAs (Field ProgrammableGate Arrays), PLDs (Programmable Logic Devices), FPOAs (FieldProgrammable Object Arrays), and CPLDs (Complex PLDs). The programmablefunction blocks may range from fine grained (combinatorial logic or lookup tables) to coarse grained (arithmetic logic units or processorcores). A programmable hardware element may also be referred to as“reconfigurable logic”.

Computer System—any of various types of computing or processing systems,including a personal computer system (PC), mainframe computer system,workstation, network appliance, Internet appliance, personal digitalassistant (PDA), television system, grid computing system, or otherdevice or combinations of devices. In general, the term “computersystem” can be broadly defined to encompass any device (or combinationof devices) having at least one processor that executes instructionsfrom a memory medium.

User Equipment (UE) (or “UE Device”)—any of various types of computersystems devices which are mobile or portable and which performs wirelesscommunications. Examples of UE devices include mobile telephones orsmart phones (e.g., iPhone™, Android™-based phones), portable gamingdevices (e.g., Nintendo DS™, PlayStation Portable™, Gameboy Advance™,iPhone™), laptops, wearable devices (e.g. smart watch, smart glasses),PDAs, portable Internet devices, music players, data storage devices, orother handheld devices, etc. In general, the term “UE” or “UE device”can be broadly defined to encompass any electronic, computing, and/ortelecommunications device (or combination of devices) which is easilytransported by a user and capable of wireless communication.

Base Station—The term “Base Station” (also called “eNB”) has the fullbreadth of its ordinary meaning, and at least includes a wirelesscommunication station installed at a fixed location and used tocommunicate as part of a wireless cellular communication system.

Processing Element—refers to various elements or combinations ofelements that are capable of performing a function in a device, such asa user equipment or a cellular network device. Processing elements mayinclude, for example: processors and associated memory, portions orcircuits of individual processor cores, entire processor cores,processor arrays, circuits such as an ASIC (Application SpecificIntegrated Circuit), programmable hardware elements such as a fieldprogrammable gate array (FPGA), as well any of various combinations ofthe above.

Automatically—refers to an action or operation performed by a computersystem (e.g., software executed by the computer system) or device (e.g.,circuitry, programmable hardware elements, ASICs, etc.), without userinput directly specifying or performing the action or operation. Thusthe term “automatically” is in contrast to an operation being manuallyperformed or specified by the user, where the user provides input todirectly perform the operation. An automatic procedure may be initiatedby input provided by the user, but the subsequent actions that areperformed “automatically” are not specified by the user, i.e., are notperformed “manually”, where the user specifies each action to perform.For example, a user filling out an electronic form by selecting eachfield and providing input specifying information (e.g., by typinginformation, selecting check boxes, radio selections, etc.) is fillingout the form manually, even though the computer system must update theform in response to the user actions. The form may be automaticallyfilled out by the computer system where the computer system (e.g.,software executing on the computer system) analyzes the fields of theform and fills in the form without any user input specifying the answersto the fields. As indicated above, the user may invoke the automaticfilling of the form, but is not involved in the actual filling of theform (e.g., the user is not manually specifying answers to fields butrather they are being automatically completed). The presentspecification provides various examples of operations beingautomatically performed in response to actions the user has taken.

Link Budget Limited—includes the full breadth of its ordinary meaning,and at least includes a characteristic of a wireless device (a UE) whichexhibits limited communication capabilities, or limited power, relativeto a device that is not link budget limited, or relative to devices forwhich a radio access technology (RAT) standard has been developed. A UEthat is link budget limited may experience relatively limited receptionand/or transmission capabilities, which may be due to one or morefactors such as device design, device size, battery size, antenna sizeor design, transmit power, receive power, current transmission mediumconditions, and/or other factors. Such devices may be referred to hereinas “link budget limited” (or “link budget constrained”) devices. Adevice may be inherently link budget limited due to its size, batterypower, and/or transmit/receive power. For example, a smart watch that iscommunicating over LTE or LTE-A with a base station may be inherentlylink budget limited due to its reduced transmit/receive power and/orreduced antenna. Wearable devices, such as smart watches, are generallylink budget limited devices. Alternatively, a device may not beinherently link budget limited, e.g., may have sufficient size, batterypower, and/or transmit/receive power for normal communications over LTEor LTE-A, but may be temporarily link budget limited due to currentcommunication conditions, e.g., a smart phone being at the edge of acell, etc. It is noted that the term “link budget limited” includes orencompasses power limitations, and thus a power limited device may beconsidered a link budget limited device.

FIG. 1—Wireless Communication System

FIG. 1 illustrates an example of a wireless cellular communicationsystem. It is noted that FIG. 1 represents one possibility among many,and that features of the present disclosure may be implemented in any ofvarious systems, as desired.

As shown, the exemplary wireless communication system includes acellular base station 102A, which communicates over a transmissionmedium with one or more wireless devices 106A, 106B, etc., as well asaccessory device 107. Wireless devices 106A, 106B, and 107 may be userdevices, which may be referred to herein as “user equipment” (UE) or UEdevices.

The base station 102 may be a base transceiver station (BTS) or cellsite, and may include hardware that enables wireless communication withthe UE devices 106A, 106B, and 107. The base station 102 may also beequipped to communicate with a network 100 (e.g., a core network of acellular service provider, a telecommunication network such as a publicswitched telephone network (PSTN), and/or the Internet, among variouspossibilities). Thus, the base station 102 may facilitate communicationbetween the UE devices 106 and 107 and/or between the UE devices 106/107and the network 100. In other implementations, base station 102 can beconfigured to provide communications over one or more other wirelesstechnologies, such as an access point supporting one or more WLANprotocols, such as 802.11 a, b, g, n, ac, ad, and/or ax, or LTE in anunlicensed band (LAA).

The communication area (or coverage area) of the base station 102 may bereferred to as a “cell.” The base station 102 and the UEs 106/107 may beconfigured to communicate over the transmission medium using any ofvarious radio access technologies (RATs) or wireless communicationtechnologies, such as GSM, UMTS (WCDMA, TDS-CDMA), LTE, LTE-Advanced(LTE-A), HSPA, 3GPP2 CDMA2000 (e.g., 1×RTT, 1×EV-DO, HRPD, eHRPD),Wi-Fi, WiMAX etc.

Base station 102 and other similar base stations (not shown) operatingaccording to one or more cellular communication technologies may thus beprovided as a network of cells, which may provide continuous or nearlycontinuous overlapping service to UE devices 106A-N and 107 and similardevices over a wide geographic area via one or more cellularcommunication technologies.

Note that at least in some instances a UE device 106/107 may be capableof communicating using any of a plurality of wireless communicationtechnologies. For example, a UE device 106/107 might be configured tocommunicate using one or more of GSM, UMTS, CDMA2000, WiMAX, LTE, LTE-A,WLAN, Bluetooth, one or more global navigational satellite systems(GNSS, e.g., GPS or GLONASS), one and/or more mobile televisionbroadcasting standards (e.g., ATSC-M/H), etc. Other combinations ofwireless communication technologies (including more than two wirelesscommunication technologies) are also possible. Likewise, in someinstances a UE device 106/107 may be configured to communicate usingonly a single wireless communication technology.

The UEs 106A and 106B are typically handheld devices such as smartphones or tablets, but may be any of various types of device withcellular communications capability. The UE 106B may be configured tocommunicate with the UE device 107, which may be referred to as anaccessory device 107. The accessory device 107 may be any of varioustypes of devices, typically a wearable device that has a smaller formfactor, and may have limited battery, output power and/or communicationsabilities relative to UEs 106. As one common example, the UE 106B may bea smart phone carried by a user, and the accessory device 107 may be asmart watch worn by that same user. The UE 106B and the accessory device107 may communicate using any of various short range communicationprotocols, such as Bluetooth.

The accessory device 107 includes cellular communication capability andhence is able to directly communicate with cellular base station 102.However, since the accessory device 107 is possibly one or more ofcommunication, output power and/or battery limited, the accessory device107 may in some instances selectively utilize the UE 106B as a proxy forcommunication purposes with the base station 102 and hence to thenetwork 100. In other words, the accessory device 107 may selectivelyuse the cellular communication capabilities of the UE 106B to conductits cellular communications. The limitation on communication abilitiesof the accessory device 107 can be permanent, e.g., due to limitationsin output power or the radio access technologies (RATs) supported, ortemporary, e.g., dues to conditions such as current battery status,inability to access a network, or poor reception.

FIG. 2 illustrates an example accessory device 107 in communication withbase station 102. The accessory device 107 may be a wearable device suchas a smart watch. The accessory device 107 may comprise cellularcommunication capability and be capable of directly communicating withthe base station 102 as shown. When the accessory device 107 isconfigured to directly communicate with the base station, the accessorydevice may be said to be in “autonomous mode.”

The accessory device 107 may also be capable of communicating withanother device (e.g., UE 106), referred to as a proxy device orintermediate device, using a short range communications protocol, andmay then use the cellular functionality of this proxy device forcommunicating cellular voice/data with the base station 102. In otherwords, the accessory device 107 may provide voice/data packets intendedfor the base station 102 over the short range link to the UE 106, andthe UE 106 may use its cellular functionality to transmit (or relay)this voice/data to the base station on behalf of the accessory device107. Similarly, the voice/data packets transmitted by the base stationand intended for the accessory device 107 may be received by thecellular functionality of the UE 106 and then may be relayed over theshort range link to the accessory device. As noted above, the UE 106 maybe a mobile phone, a tablet, or any other type of handheld device, amedia player, a computer, a laptop or virtually any type of wirelessdevice. When the accessory device 107 is configured to indirectlycommunicate with the base station using the cellular functionality of anintermediate or proxy device, the accessory device may be said to be in“relay mode.”

The accessory device 107 may include a processor that is configured toexecute program instructions stored in memory. The accessory device 107may perform any of the method embodiments described herein by executingsuch stored instructions. Alternatively, or in addition, the accessorydevice 107 may include a programmable hardware element such as an FPGA(field-programmable gate array), or other circuitry, that is configuredto perform any of the method embodiments described herein, or anyportion of any of the method embodiments described herein.

The accessory device 107 may include one or more antennas forcommunicating using two or more wireless communication protocols orradio access technologies. In some embodiments, the UE device 106 mightbe configured to communicate using a single shared radio. The sharedradio may couple to a single antenna, or may couple to multiple antennas(e.g., for MIMO) for performing wireless communications. Alternatively,the UE device 106 may include two or more radios. For example, the UE106 might include a shared radio for communicating using either of LTE(or LTE-Advanced) or Bluetooth, and separate radios for communicatingusing each of LTE-Advanced and Bluetooth. Other configurations are alsopossible.

The accessory device 107 may be any of various types of devices that, insome embodiments, has a smaller form factor relative to a conventionalsmart phone, and may have one or more of limited communicationcapabilities, limited output power, or limited battery life relative toa conventional smart phone. As noted above, in some embodiments, theaccessory device 107 is a smart watch or other type of wearable device.As another example, the accessory device 107 may be a tablet device,such as an iPad, with WiFi capabilities (and possibly limited or nocellular communication capabilities) which is not currently near a WiFihotspot and hence is not currently able to communicate over WiFi withthe Internet. Thus, the term “accessory device” refers to any of varioustypes of devices that in some instances have limited or reducedcommunication capabilities and hence may selectively andopportunistically utilize the UE 106 as a proxy for communicationpurposes for one or more applications and/or RATs. When the UE 106 iscapable of being used by the accessory device 107 as a proxy, the UE 106may be referred to as a companion device to the accessory device 107.

FIG. 3—Example Block Diagram of an Accessory Device

FIG. 3 illustrates one possible block diagram of an accessory device107. As shown, the accessory device 107 may include a system on chip(SOC) 300, which may include portions for various purposes. For example,as shown, the SOC 300 may include processor(s) 302 which may executeprogram instructions for the accessory device 107, and display circuitry304 which may perform graphics processing and provide display signals tothe display 360. The processor(s) 302 may also be coupled to memorymanagement unit (MMU) 340, which may be configured to receive addressesfrom the processor(s) 302 and translate those addresses to locations inmemory (e.g., memory 306, read only memory (ROM) 350, Flash memory 310).The MMU 340 may be configured to perform memory protection and pagetable translation or set up. In some embodiments, the MMU 340 may beincluded as a portion of the processor(s) 302.

The accessory device 107 may also include other circuits or devices,such as the display circuitry 304, radio 330, connector I/F 320, and/ordisplay 360. In some embodiments, the accessory device includes or iscoupled to a battery (not shown) and may include sensor circuitry (notshown) that is configured to assert various signals based on batteryvoltage characteristics such as voltage level, voltage slope, voltagepattern detection, etc.

In the embodiment shown, ROM 350 may include a bootloader, which may beexecuted by the processor(s) 302 during boot up or initialization. Asalso shown, the SOC 300 may be coupled to various other circuits of theaccessory device 107. For example, the accessory device 107 may includevarious types of memory, a connector interface 320 (e.g., for couplingto a computer system), the display 360, and wireless communicationcircuitry (e.g., for communication using LTE, CDMA2000, Bluetooth, WiFi,NFC, GPS, etc.).

The accessory device 107 may include at least one antenna, and in someembodiments multiple antennas, for performing wireless communicationwith base stations and/or other devices. For example, the accessorydevice 107 may use antenna 335 to perform the wireless communication. Asnoted above, the UE may in some embodiments be configured to communicatewirelessly using a plurality of wireless communication standards orradio access technologies (RATs).

As described herein, the accessory device 107 may include hardware andsoftware components for implementing methods according to embodiments ofthis disclosure. The processor 302 of the accessory device 107 may beconfigured to implement part or all of the methods described herein,e.g., by executing program instructions stored on a memory medium (e.g.,a non-transitory computer-readable memory medium). In other embodiments,processor 302 may be configured as a programmable hardware element, suchas an FPGA (Field Programmable Gate Array), or as an ASIC (ApplicationSpecific Integrated Circuit).

It is noted that the UEs 106A and 106B shown in FIG. 1 may have asimilar architecture to that described above.

Exemplary Control of Transmission Energy Budget

FIG. 4 is a block diagram illustrating exemplary modules, which may belocated in wireless communication circuitry 330 in some embodiments. Inother embodiments, these modules may be implemented elsewhere. Theillustrated modules may be implemented using software, firmware, ordedicated circuitry, in various embodiments. In the illustratedembodiment, wireless communication circuitry 330 includes transmission(TX) energy budget control module 410, LTE L1 module 420, WCDMA L1module 430, LTE preUVLO handling module 440, and WCDMA preUVLO handlingmodule 450.

UVLO refers to an “undervoltage-lockout” signal which is used to turnoff power to particular circuitry (or an entire device) when supplyvoltage drops below a threshold value. For example, if the batteryvoltage from an accessory device drops below a certain threshold (oftendue to a current spike, e.g., when multiple components are operatingsimultaneously), a UVLO signal may power down the accessory device orcomponents thereof. In some embodiments a “preUVLO” signal indicatesthat a UVLO signal may be asserted soon, e.g., because supply voltageconditions are deteriorating. In some instances, taking action based onthe preUVLO signal may enable the device to avoid asserting UVLO.

Therefore, in the illustrated embodiment, modules 440 and 450 areconfigured to receive or generate and handle preUVLO signals. Thesemodules are included in RF drivers, in some embodiments. In otherembodiments, these modules are implemented using dedicated circuitry.

In the illustrated embodiment, L1 modules 420 and 430 are configured toperform L1 physical layer processing for LTE and WCDMA communicationsrespectively. In some embodiments, these modules are implemented infirmware.

TX energy budget control module 410 (which may also be referred to as“energy budget module 410”) is configured to schedule wirelesstransmissions based on an energy budget, in some embodiments. In someembodiments, energy budget module 410 determines the energy budget basedon battery signals (such as a preUVLO signal), thermal signals, previoususe of energy budget, blanked transmissions, etc. In some embodiments,module 410 is software, while in other embodiments module 410 isimplemented, at least in part, using dedicated circuitry.

In some embodiments, energy budget module 410 is configured to rapidlyadjust energy budget by blanking scheduled transmissions in response toa battery signal such as a preUVLO signal. In some embodiments, energybudget module 410 is configured to blank any scheduled wirelesstransmissions during intervals in which preUVLO is asserted.

As used herein, the term “blanking” refers to canceling a scheduledwireless transmission such that the transmission is not performed. Notethat some transmissions may be allowed to occur during a blankinginterval while other transmissions (e.g., with different scheduled timeand/or frequency resources) may be blanked.

In some embodiments, energy budget module 410 is also configured toperform longer term budget control. In some embodiments, energy budgetmodule 410 is configured to determine energy budgets at the granularityof periods or cycles of operation. In some disclosed embodiments, 40millisecond cycles are implemented, but cycles of various lengths may beused in various other embodiments. In some embodiments, the cycle lengthis determined to provide fast response for power and thermal controlwhile providing enough samples for handling preUVLO signaling. 40 ms maymap, in some embodiments, to the duration of two audio frames, a commonvoice over LTE (VoLTE) discontinuous reception (DRX) length, and/or atransmission time interval (TTI) commonly used in WCDMA communications,for example. Once the energy budget for a particular cycle has beendetermined, wireless communication circuitry 330 may scheduletransmission for that cycle to stay within the budget (although blankingof scheduled transmissions may occur based on the preUVLO signal, forexample).

The following parameters may be used in some embodiments in the contextof determining energy budget for a cycle. These parameters are discussedfor illustrative purposes but are not intended to limit the scope of thepresent disclosure. In other embodiments, other similar parameters maybe used to determine energy budget.

-   -   E-preUVLO: energy that is not used in a cycle because of        blanking triggered by preUVLO signals. For example, if two        transmissions in a given cycle are blanked, E-preUVLO for that        cycle corresponds to the sum of the energy that the two        transmissions would have used.    -   E-cltm: a maximum allowed energy budget in a cycle that is        assigned based on component-level thermal management (cltm).        This is one example of a parameter based on thermal information.        Each component may include one or more thermal sensors        configured to generate information that may be used to determine        E-cltm, in some embodiments.    -   E-budget: TX energy budget for a cycle.    -   E-scheduled: TX energy that is scheduled by baseband for use in        a given cycle.    -   E-used: TX energy used in a cycle. E-used=E-scheduled−E-preUVLO.        Said another way, the energy that is used in a given cycle is        the energy of scheduled transmissions during the cycle minus the        energy of scheduled transmissions that are blanked.    -   E-leftover: the budgeted TX energy in a cycle that is not used.        E-leftover=E-budget−E-used. Said another way, the leftover        energy for a given cycle is the difference between the energy        budget for that cycle and the actual energy used to transmit in        that cycle.    -   E-min, E-max: the minimum and maximum budget respectively that        can be used for a cycle. In some embodiments, these parameters        are programmable. E-min may be low or may be zero, in some        situations or embodiments.    -   T-pp: a configurable timer which is started or re-started when        the preUVLO signal is received in a cycle. In various examples        herein, the T-pp duration is 120 ms, but the duration may be        programmable or may be fixed at some other value. In some        embodiments, accessory device 107 operates in a “peak power        mode” as long as T-pp is running but operates in a “thermal        mode” otherwise. Speaking generally, T-pp is used to measure an        interval that occurs subsequent to assertion of a battery        signal.

In some embodiments, energy budget module 410 is configured to determineE-budget for a current cycle differently depending on whether it isoperating in peak power mode or in thermal mode. In some embodiments, inthermal mode, E-budget is the lesser of (1) E-leftover from previouscycle+E-cltm for current cycle or (2) E-max. This may allow unusedenergy from the previous cycle to augment the current thermal budget, solong as E-max is not exceeded. In some embodiments, E-leftover is 0 ifE-cltm is changed in a current cycle.

In some embodiments, in peak power mode, E-budget is the lesser of (1)E-cltm for the current cycle or (2) the greater of ((a) E-used from themost recent cycle in which preUVLO was asserted or (b) E-min). In someembodiments, this may result in the budget being restricted to theamount of energy used in the cycle that blanking occurred in situationswhere this energy is smaller than E-cltm and greater than E-min.

In some LTE embodiments, E-min corresponds to transmitting at full power(e.g., 23 dBm) five times (e.g., one PDU transmission and fourretransmissions). In some WDCMA embodiments, E-min corresponds totransmitting for 10 ms of DPCCH transmissions at peak power. In otherembodiments, E-min may be have any of various appropriate values and/ormay be programmable.

FIG. 5 is a flow diagram illustrating a method for determining E-budgetfor a cycle, according to some embodiments. The method shown in FIG. 5may be used in conjunction with any of the computer circuitry, systems,devices, elements, or components disclosed herein, among others. Invarious embodiments, some of the method elements shown may be performedconcurrently, in a different order than shown, or may be omitted.Additional method elements may also be performed as desired.

At 502, in the illustrated embodiment, energy budget module 410determines whether the device is in peak power mode or in thermal modebased on whether the T-pp timer is running. If the timer is running,flow proceeds to 504.

At 504, in the illustrated embodiment, energy budget module 410determines E-budget based on energy used in the last cycle in whichblanking occurred (E-used), E-min, and E-cltm, according to theillustrated equation: E-budget=min(max(E-used, E-min), E-cltm).

If the T-pp timer is not running in step 502, flow proceeds to 506 inwhich energy budget module 410 determines E-budget based on thermalinformation (E-ctlm in the illustrated embodiment) and an amount ofunused budget from the previous cycle, according to the illustratedequation: E-budget=E-cltm+E-leftover.

At 508, in the illustrated embodiment, E-leftover for the current cycleis set to zero if E-cltm changed. This may avoid excess energy usagecaused by leftover budget in cases where thermal conditions deteriorate,for example. In other embodiments, E-leftover may not be set to zerowhen E-cltm changes, but may be adjusted in response to the change.

At 510, in the illustrated embodiment, wireless communication circuitry330 schedules transmissions for the current cycle such that E-scheduledis smaller than or equal to E-budget. In some embodiments, thescheduling may be performed such that E-scheduled is also smaller thanE-max. Examples of such scheduling for LTE and WCDMA communications arediscussed in further detail below.

During a given cycle (e.g., beginning at step 502 and ending at step 516or 518 in the illustrated embodiment), wireless communication circuitry330 may blank one or more scheduled transmissions in response to preUVLObeing asserted. In other cycles, no blanking may occur.

At 512, in the illustrated embodiment, energy budget module 410determines E-used based on E-scheduled and E-preUVLO. Energy budgetmodule 410 may determine E-used near the end of the cycle such thatE-preUVLO reflects any blanking that occurred during the cycle.

At 514, in the illustrated embodiment, energy budget module 410determines whether E-preUVLO was asserted during the current cycle. Ifso, flow proceeds to 516 and the T-pp timer is started or restarted(e.g., to 120 ms). If not, flow proceeds to 518 and E-leftover is setbased on the current budget and the energy used in the current cycle:E-leftover=E-budget−E-used. From 516 and 518, flow proceeds back to 502and the method may be repeated for one or more subsequent cycles. Insome embodiments, at least a portion of the method of FIG. 5 is repeatedfor each cycle and associated time period.

In some embodiments, the disclosed method may allow for efficientwireless transmission of data while satisfying both battery and thermalconstraints during operation of accessory device 107.

Energy Budget Examples

FIG. 6A is a diagram illustrating exemplary carryover of leftoverbudget, according to some embodiments. FIG. 6A shows four exemplary 40ms cycles of operation of wireless communication circuitry 330. In theillustrated embodiment, each rectangle represents a 4 ms interval, whichmay correspond to a transmission in TTI bundling mode for a hybridautomatic repeat request (HARQ) process. In the illustrated embodiment,shaded blocks of a particular shading style correspond to the same HARQprocess while unshaded blocks indicate that transmissions are notscheduled during the corresponding time interval. To facilitateexplanation, in the illustrated embodiment all transmissions areperformed at 23 dBm.

In the illustrated example, thermal parameters do not change and E-cltmfor each cycle is 20 dBm*40 (which may correspond to transmitting at 20dBm for 40 ms or at 23 dBm for 20 ms). In the example of FIG. 6A,preUVLO is not asserted at all, so energy budget module 410 operates inthermal mode.

For the cycle beginning at 0 ms, E-budget is 20 dBm*40. E-leftover iszero after the cycle beginning at 0 ms, because the entire energy budgetis used for the illustrated five transmissions, transmitting at 23 dBmfor 20 ms (E-scheduled=E-budget).

For the cycle beginning at 40 ms, E-budget is 20 dBm*40, but E-scheduledis zero. Therefore, E-leftover is the entire E-budget of 20 dBm*40 atthe beginning of the next cycle.

For the cycle beginning at 80 ms, the current budget includes theleftover from the previous cycle and is 20 dBm*80. In the illustratedexample, this entire budget is used and transmissions occur in each 4 msinterval. Therefore, E-leftover is zero after this cycle. Note that insome embodiments, if E-max were lower than 20 dBm*80, then only aportion of the budget would be scheduled in this cycle and some leftovermight carry over to the next cycle.

For the cycle beginning at 120 ms, in the illustrated example, thecurrent budget is 20 dBm*40, which is all used in this cycle.

FIG. 6B is a diagram illustrating exemplary blanking caused by assertionof a battery signal (preUVLO in this example). In the illustratedexample, four and a half 40 ms cycles are shown. The solid rectangle at24 ms corresponds to a scheduled transmission that was blanked in thecycle beginning at 0 ms. In the illustrated embodiment, this blanking iscaused by assertion of preUVLO during the blanked 4 ms interval.

For the cycle beginning at 0 ms, E-budget is 20 dBm*40. Because preUVLOwas asserted during this cycle, energy budget module 410 starts the T-pptimer at the end of the cycle.

Therefore, for the cycle beginning at 40 ms, E-budget is determinedbased on E-used (20 dBm*32), E-min, and E-cltm (20 dBm*40). In theillustrated example, E-used is greater than E-min and smaller thanE-cltm, so E-budget=E-used. Said another way, for an interval afterassertion of the battery signal, cycle budget is limited to the energyused in the cycle in which blanking occurred. In the cycle beginning at40 ms, none of the budget is actually used.

For the cycle beginning at 80 ms, the current budget remains 20 dBm*32because carryover of leftover budget is not implemented in peak powermode, in this embodiment. For this cycle, three transmissions areperformed (note that four transmissions could be performed within theenergy budget).

For the cycle beginning at 160 ms, the timer is no longer running andthe budget reverts back to being based on E-cltm, which has not changedfrom the first cycle in the illustrated example.

Exemplary LTE Scheduling Techniques

In some LTE embodiments, wireless communication circuitry 330 mayimplement one or more of the following techniques when schedulingtransmissions based on the determined energy budget for a given cycle.

When transmitting on PUSCH, wireless communication circuitry 330 maymeasure the average number of HARQ transmission needed for transportblocks (TB) with different sizes and estimate the total TX energy neededfor a transport block in a cycle. This may allow wireless communicationcircuitry 330 to determine whether transmissions can be performed usingthe allocated energy budget. In some embodiments, wireless communicationcircuitry 330 gives highest priority to signaling messages (e.g., RRCmessages).

In some embodiments, wireless communication circuitry 330 prioritizes TBretransmissions over new transmissions for each active HARQ process. Insome embodiments, wireless communication circuitry 330 only allows a newTB transmission on an empty HARQ process when the difference betweenE-budget and the estimated TX energy for the new TB is greater than athreshold value. In some embodiments, when the threshold is not met,wireless communication circuitry 330 is configured to adjust a bufferstatus report (BSR) to prevent the network from assigning a grant for anew TB.

Note that, in some embodiments, giving lower priority to new TBs mayresult in discarding protocol data units (PDUs) from a Packet DataConvergence Protocol (PDCP) buffer. In some embodiments, to avoid orreduce such discarding, wireless communication circuitry 330 isconfigured to reduce voice codec rate for UL voice frames and/or reducemaximum IP packet size by decreasing the maximum transmission unit (MTU)size.

In some embodiments, wireless communication circuitry 330 is configuredto prioritize retransmissions with redundancy version (RV) zero overother RV numbers. This may increase energy efficiency if uplink data canbe decoded from an initial RV, in some embodiments.

In some embodiments, wireless communication circuitry 330 is configuredto transmit at a lower power in a given cycle rather than blanking ordelaying transmissions. For example, consider a case where atransmission requires 23 dBm*4, but only 20 dBm*4 is available in thecurrent E-budget. In some embodiments, if the difference betweenrequired power and allowed power is smaller than a threshold value,wireless communication circuitry 330 is configured to perform thetransmission using the allowed power in the budget (e.g., perform thetransmission at 20 dBm*4 in the previous example). This may be referredto as power back-off. In some embodiments, if the difference is greaterthan the threshold value, wireless communication circuitry 330 isconfigured to blank and/or reschedule the transmission.

In some embodiments, wireless communication circuitry 330 may transmitACK/NAK messages on PUCCH for PDSCH and/or PDCCH if there is not enoughTX power for PUSCH. In some embodiments, for PUCCH, wirelesscommunication circuitry 330 is configured to perform power back-offand/or blanking based on a threshold value, as described above withreference to PUSCH (although the threshold may be different than thethreshold for PUSCH).

Exemplary WCDMA Scheduling Techniques

In some WCDMA embodiments, wireless communication circuitry 330implements one or more of the following techniques when schedulingtransmissions based on the determined energy budget for a given cycle.

In some embodiments, wireless communication circuitry 330 is configuredto give highest priority to the high-speed dedicated physical controlchannel (HS-DPCCH) for high-speed downlink packet access (HSDPA) ACK/NAKmessages. In some embodiments, wireless communication circuitry 330 isconfigured to give RRC/NAS signaling messages on the dedicated physicaldata channel (DPDCH) higher priority than other voice or data channels.In some embodiments, wireless communication circuitry 330 is configuredto use a transport format combination (TFC) and/or e-TFCI selection fordata on DPDCH and/or E-DPDCH to limit UL data throughput and reduce TXpower consumption, based on a current energy budget.

In some embodiments, wireless communication circuitry 330 may determinewhether to use power back-off or blanking based on a threshold differentbetween allowed power in the budget and required power, e.g., asdiscussed above with reference to LTE embodiments. In some embodiments,wireless communication circuitry 330 is configured to satisfy an energybudget in a cycle by implementing multiple short TX blanking intervalsrandomly distributed or distributed in a pre-determined sequence in thecycle to attain a desired TX duty cycle. It may be more difficult toreduce TX power in WCDMA than in LTE without destroying the transmissiontime interval (TTI) of frames, therefore such short TX blanking may beused to schedule transmissions within a determined TX energy budget.

Power back-off or blanking may be performed in various WCDMA scenarios.During voice communications, for example, an 80% duty cycle may bemaintained on DPDCH for voice data and an 80% duty cycle on DPCCH forcontrol information. During silence or listen intervals, a 25% dutycycle may be maintained on DPCCH only. During data upload, a 50% dutycycle may be maintained for data on DPDCH with 20 ms transmission timeintervals (e.g., by restricting the DPDCH transport format combination(TFC) selection procedure), while a 90% duty cycle may be maintained forDPCCH. In another data upload scenario, a 20% duty cycle may bemaintained on E-DPDCH (e.g., by restricting E-DPDCH TFC selectionprocedure) with a transmission time intervals of 2 ms along with an 80%duty cycle on DPDCH with a transmission time intervals of 10 ms and an80% duty cycle on DPCCH. The particular duty cycles, channels used,types of communications, etc. may be adjusted to meet the transmissionenergy budget in each time cycle (e.g., 40 ms in some embodiments).

Although various LTE and WCDMA techniques have been disclosed herein forpurposes of illustration, these technologies are not intended to limitthe scope of the present disclosure. In other embodiments, similartechniques may be used in any of various appropriate radio accesstechnologies.

High-Priority Transmission Mode

In some embodiments, wireless communication circuitry 330 is configuredto operate in a high-priority mode. In some embodiments, wirelesscommunication circuitry 330 asserts a hardware signal to othercomponents when operating in this mode. The other components may reduceenergy usage until the signal is de-asserted. In some embodiments,wireless communication circuitry 330 operates in the high-priority modefor critical RRC signaling messages, for example. In some embodiments,wireless communication circuitry 330 is configured not to utilize theenergy budget techniques discussed above when operating in thehigh-priority transmission mode.

Exemplary Method

FIG. 7 is a flow diagram illustrating a method for operating wirelesscircuitry, according to some embodiments. The method shown in FIG. 7 maybe used in conjunction with any of the computer circuitry, systems,devices, elements, or components disclosed herein, among others. Invarious embodiments, some of the method elements shown may be performedconcurrently, in a different order than shown, or may be omitted.Additional method elements may also be performed as desired.

At 702, in the illustrated embodiment, wireless communication circuitry330 determines a respective wireless transmission energy budget for eachof a plurality of time periods, where the wireless transmission energybudget for at least a first period is based on an amount of unusedenergy budget in a previous period. In some embodiments, the firstperiod corresponds to a first mode of operation which may be a thermalmode of operation. The period from 80 ms to 120 ms in FIG. 6A is oneexample of such a period. The energy budget for the first period mayfurther be determined based on thermal information.

In some embodiments, wireless communication circuitry 330 also operatesin a second mode of operation (e.g., a peak power mode) in which thewireless transmission energy budget for one or more time periods isbased on an amount of energy used for wireless transmissions in a mostrecent period in which transmissions were blanked in response to abattery signal. The three periods beginning at 40 ms and ending at 160ms in FIG. 6B are examples of such periods.

At 704, in the illustrated embodiment, wireless communication circuitry330 schedules wireless transmissions for the plurality of time periodsbased on the respective energy budgets. This may be performed byscheduling HARQ transmissions or retransmissions in LTE, insertingblanking intervals into WCDMA frames to achieve a desired duty cycle,etc.

At 706, in the illustrated embodiment, wireless communication circuitry330 causes at least a portion of the scheduled wireless transmissions tobe performed for the plurality of time periods. In some embodiments,some of the scheduled transmissions may be blanked, e.g., when theyintersect with assertion of a battery signal such as preUVLO.

Embodiments of the present disclosure may be realized in any of variousforms. For example some embodiments may be realized as acomputer-implemented method, a computer-readable memory medium, or acomputer system. Other embodiments may be realized using one or morecustom-designed hardware devices such as ASICs. Still other embodimentsmay be realized using one or more programmable hardware elements such asFPGAs.

In some embodiments, a non-transitory computer-readable memory mediummay be configured so that it stores program instructions and/or data,where the program instructions, if executed by a computer system, causethe computer system to perform a method, e.g., any of a methodembodiments described herein, or, any combination of the methodembodiments described herein, or, any subset of any of the methodembodiments described herein, or, any combination of such subsets.

In some embodiments, a device (e.g., a UE 106 or accessory device 107)may be configured to include a processor (or a set of processors) and amemory medium, where the memory medium stores program instructions,where the processor is configured to read and execute the programinstructions from the memory medium, where the program instructions areexecutable to implement a method, e.g., any of the various methodembodiments described herein (or, any combination of the methodembodiments described herein, or, any subset of any of the methodembodiments described herein, or, any combination of such subsets). Thedevice may be realized in any of various forms.

Although the embodiments above have been described in considerabledetail, numerous variations and modifications will become apparent tothose skilled in the art once the above disclosure is fully appreciated.It is intended that the following claims be interpreted to embrace allsuch variations and modifications.

What is claimed is:
 1. An apparatus, comprising: one or more processingelements configured to: determine a respective wireless transmissionenergy budget for each of a plurality of time periods, wherein thewireless transmission energy budget for at least a first period is basedon an amount of unused energy budget in a previous period; schedulewireless transmissions for the plurality of time periods based on therespective energy budgets; blank one or more of the scheduledtransmissions in at least one of the time periods in response to abattery signal; and cause at least a portion of the scheduled wirelesstransmissions to be performed for the plurality of time periods.
 2. Theapparatus of claim 1, wherein the energy budget for the first period isfurther based on thermal information for the apparatus.
 3. The apparatusof claim 2, wherein the thermal information is component-level thermalinformation based on thermal sensors included in a plurality ofcomponents of the apparatus.
 4. The apparatus of claim 1, wherein thebattery signal is a pre-undervoltage-lockout (UVLO) signal.
 5. Theapparatus of claim 1, wherein one or more processing elements areconfigured not to consider leftover energy budget from a previous periodin determining the energy budget for a current period if thermalinformation for the apparatus changed from the previous period to thecurrent period.
 6. The apparatus of claim 1, wherein to schedulewireless transmissions for at least one of the time periods, the one ormore processing elements are configured to prioritize retransmissionsover new transmissions.
 7. The apparatus of claim 1, wherein, toschedule wireless transmissions for code division multiple access (CDMA)communications in at least one of the time periods, the one or moreprocessing elements are configured to perform blanking during intervalsrandomly distributed in the at least one of the time periods in order tosatisfy the determined energy budget for the at least one of the timeperiods.
 8. A non-transitory computer-readable medium havinginstructions stored thereon that are executable by a computing device toperform operations comprising: determining a respective wirelesstransmission energy budget for each of a plurality of time periods,wherein in a first mode of operation the wireless transmission energybudget for at least a first period is based on an amount of unusedenergy budget in a previous period and thermal information for thecomputing device; scheduling wireless transmissions for the plurality oftime periods based on the respective energy budgets; blanking one ormore of the scheduled wireless transmissions in at least one of the timeperiods in response to a battery signal; and causing at least a portionof the scheduled wireless transmissions to be performed for theplurality of time periods.
 9. The non-transitory computer-readablemedium of claim 8, wherein in a second mode of operation the wirelesstransmission energy budget for at least a first period is based on anamount of energy used for wireless transmissions in a most recent periodin which transmissions were blanked in response to the battery signal.10. The non-transitory computer-readable medium of claim 9, wherein theoperations further comprise: operating in the second mode of operationfor a predetermined interval subsequent to assertion of the batterysignal.
 11. The non-transitory computer-readable medium of claim 10,wherein the battery signal indicates detection of a potentialundervoltage lockout (UVLO) condition.
 12. The non-transitorycomputer-readable medium of claim 8, wherein the operations furthercomprise, in the first mode of operation, determining a wirelesstransmission energy budget for one of the periods based on the thermalinformation and not based on leftover energy budget from a previousperiod, in response to a change in the thermal information.
 13. Amethod, comprising: determining, by a wireless communication apparatus,a respective wireless transmission energy budget for each of a pluralityof time periods, wherein the wireless transmission energy budget for atleast a first period is based on an amount of unused energy budget in aprevious period; scheduling, by the wireless communication apparatus,wireless transmissions for the plurality of time periods based on therespective energy budgets; blanking one or more of the scheduledwireless transmissions in at least one of the plurality of time periodsin response to a battery signal; and causing, by wireless communicationapparatus, at least a portion of the scheduled wireless transmissions tobe performed for the plurality of time periods.
 14. The method of claim13, further comprising: operating in a first mode of operation in whichthe wireless transmission energy budget for one or more time periods isbased on an amount of unused energy budget in a previous period; andoperating in a second mode of operation in which the wirelesstransmission energy budget for one or more time periods is based on anamount of energy used for wireless transmissions in a most recent periodin which transmissions were blanked in response to the battery signal.15. The method of claim 14, further comprising: determining, in thesecond mode of operation, the wireless transmission energy budget for atleast a second period as the smaller of: (1) the amount of energy usedfor wireless transmissions in the most recent period in whichtransmissions were blanked in response to the battery signal or (2) anenergy budget based on thermal information.
 16. The method of claim 14,further comprising: operating in the second mode of operation formultiple time periods in response to assertion of the battery signal.17. The method of claim 13, further comprising: determining the wirelesstransmission energy budget for at least the first period as an energybudget based on thermal information for the wireless communicationapparatus plus unused energy budget from the previous period.
 18. Themethod of claim 13, wherein the battery signal indicates detection of apotential undervoltage lockout (UVLO) condition.
 19. The method of claim13, wherein to schedule wireless transmissions, the method furthercomprises: blanking one or more transmissions during intervals randomlydistributed in at least one of the time periods based on the respectiveenergy budget of the at least one time period.
 20. The method of claim13, wherein to schedule wireless transmissions, the method furthercomprises: blanking one or more transmissions distributed in apre-determined sequence of at least one of the time periods based on therespective energy budget of the at least one time period.